1. Field of the Invention
The present invention relates to a drive circuit for at least one light-emitting diode, and in particular to such a drive circuit wherein the light-emitting diode is connected in a feed circuit which is driven via a connecting line by a transistor push-pull circuit.
2. Description of the Prior Art
A drive circuit for a light-emitting diode utilizing a transistor push-pull circuit connected to the light-emitting diode via a connecting line consisting of a resistor and a capacitor connected in parallel is known from German AS No. 28 50 044. Depending upon which of the two transistors in the push-pull circuit is blocking or conducting, the light-emitting diode is either short-circuited or receives additional feed current from the push-pull circuit. In order that the light-emitting diode be reliably inhibited in the short-circuited state, the effective potential difference at the light-emitting diode must be smaller than the threshold voltage of the light-emitting diode. In many instances it is therefore necessary in order to achieve this result that the feed voltages of the push-pull circuit and of the feed circuit containing the light-emitting diode be different. Such a voltage differential would, however, not normally be desired in the absence of the light-emitting diode.